


Nirvana Descention

by WrestleCrazyGamer



Category: Ao no Exorcist | Blue Exorcist
Genre: Alternate Universe - Canon Divergence, F/M, Post-Canon, Will add more as chapters go on
Language: English
Status: In-Progress
Published: 2018-02-23
Updated: 2018-02-26
Packaged: 2019-03-23 03:08:01
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 3,313
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13778379
Author URL: https://archiveofourown.org/users/WrestleCrazyGamer/pseuds/WrestleCrazyGamer
Summary: The reign of Satan is over. The demon world's activity in the human world has died down considerably, but it's no reason for True Cross to stop training new Exorcists. Yukio is still an instructor and is about to get a student he wasn't counting on...*Please leave feedback - what you like, what you don't like, what may need work, etc.*





	1. New Student

It was the morning of the second week at True Cross Academy’s cram school. Yukio approached the door to begin class and opened it to find Mephisto was there at the podium making the students nervous.

“Director, it’s a surprise to see you here.” Yukio addressed him.

“You have a new student joining your class today, Professor Okumura. I hope you’ll treat him nicely.” Mephisto smiled.

“Oh? Well at least they won’t be too far behind.” Yukio smiled looking past him immediately freezing in place seeing a wagging tail.

“This is Shinku Okumura, your nephew.” Mephisto introduced the male student behind him.

He had messy black hair that turned blond at the ends, demon ears, and a demon tail. Different from Rin though, the tip of his tail seemed to be permanently lit with a crimson flame. His smile screamed of his relation to Yukio’s brother. Strapped to his waist by a black strap was a Japanese Sword bearing red wrapping, a lapis colored guard and pommel, and a dark ruby-colored scabbard.

“I see… my nephew…” Yukio spoke trying to hide his agitation.

“Hiya Uncle Yukio! You can shorten my name to Shin if you want to. Everyone does.” Shin beamed.

“In that case… Shin… do you want to share anything about yourself with the class…?” Yukio asked with his eyebrow twitching a bit.

“Sure. I just look like a demon, I’m only half. My mom’s the human parent. Oh, and my tail flame only ignites things if I want it to so it’s harmless in any other situation.” Shin smiled with his arms nonchalantly behind his head.

“That sword at your waist is a Demon Sword isn’t it? I don’t recognize it from the book of recorded Demon Swords.” Yukio pointed out.

“It was specially forged for me. Its name is Flame Eater, and it’s supposed to help me control my flames by devouring any excessive flames that comes out during battle.” Shin explained.

“I see. Be sure that it’s properly registered.” Yukio told him.

“Oh he did that when he enrolled. Rin made sure to cover all his bases before trouble arose.” Mephisto smiled.

“I see. You may take your seat now.” Yukio spoke.

After class ended Yukio stopped Shin at the door. He wanted all the other students to be gone before he talked. After the door closed he turned his attention to Shin, who looked confused.

“Why didn’t Rin tell me he had a son?” Yukio asked him.

“Dad said you and him weren’t exactly on speaking terms.” Shin replied.

“We’ve been distant sure but not on speaking terms? Why did you choose True Cross Academy?” Yukio asked him.

“A lot of people are nervous or even scared around half demons like me, so I want to become someone that’ll stand as a pillar for half demons the world over… proof that just because we have demon heritage doesn’t mean we’re destined to be evil.” Shin answered.

“You know becoming an exorcist won’t be easy right?” Yukio asked squinting his eyes trying to analyze him.

“If it was easy everyone would be an exorcist. I’m tired of people being afraid of me, so I’m willing to hit the books for it. Brute strength will only gets me so far after all.” Shin replied catching him off guard.

“What’s your philosophy on demonic powers?” Yukio asked.

“They should only be used if it’s absolutely necessary.” Shin answered.

“I see. You’re free to go now.” Yukio told him.

Yukio returned to his home that evening and the instant he opened the door a baby bottle nailed him in the forehead. Inside was Shura, holding a sleeping baby girl in a blanket. Yukio stood and she was in his face in a second.

“You’re over an hour late! What the hell was keeping you?” Shura growled.

“I had to make sure a new student was going to be okay.” Yukio groaned rubbing his injury.

“Bullshit you were suspicious of our nephew.” Shura scoffed.

“How’d you know?” Yukio questioned.

“He dropped by this morning to formally introduce himself. He missed Setsuna before she could meet him, but I’m sure she’ll see him tomorrow since her suspension is up.” Shura sighed.

“When did she get suspended?” Yukio asked.

“How did you not know? She wasn’t in class at the cram school either and you teach that. The story is that she went too far disciplining some delinquents and was given a week’s suspension. Thanks to many appeals from the council president she’s still disciplinary chair as long as she doesn’t go putting more students in the hospital.” Shura told him.

“She put them in the hospital?!” Yukio exclaimed waking the baby.

“Now look what you did!” Shura scolded him.

“You’ve been shouting just as much as me!” Yukio shot back.

“Stop shouting and soothe her already!” a girls’ voice shouted from inside the house.

Elsewhere at a special dorm, Shin was eating dinner contently. He let out a loud belch before taking his tray to the counter. Shin then hurried to his room on the second floor to start on his homework. He set a stopwatch and worked as fast as he could until he hit the stopwatch again.

“Thirty minutes… I can be faster…” Shin scoffed taking out his notebook.

He copied all the problems including new ones and kept working. His desk was covered in papers by seven. His pencil was worn all the way down to the metal from constant sharpening and his eraser was almost nonexistent.

“I think that’s enough for now… only managed to cut down to twenty-five minutes though. Eh, test isn’t until Friday so I’ve got time. I can’t wait to knock Uncle Yukio’s socks off with my blinding speed. Just you wait and see… I’ll finish first in class with a 100 guaranteed.” Shin cackled to himself.

The days went by until Friday. Shin already prepped his pencil and eraser when the door opened one extra time than he was used to. The one to enter was a girl student with long red hair that faded to brown at the ends. Her figure was masculine yet femininely gifted. Instead of the school blazer she wore a black military-style frock coat. She was carrying a large black instrument case that was nearly her size like it was weightless too.

“Who’s that?” Shin asked.

“You don’t know? That’s Setsuna Okumura, a second year and Disciplinary Chair of the Student Council. Anyone that steps out of line even the slightest is at risk of meeting her case… and to a lesser extent the weapon hidden inside depending on the offense…” the girl student behind him whispered.

“Judging by the length, depth, and width of the case it’s either a firearm, an ax, or a sword. There’s also the possibility that the case itself has some kind of mechanism inside it.” Shin spoke analyzing the case as Setsuna took her seat.

“You’ll be given one hour to complete this test. Remain silent until the allotted time is over or everyone finishes. Unless you have detention or an urgent matter to discuss with me, you’re free to leave once you finish. Begin as soon as you receive your test.” Yukio explained to them as he passed out the tests.

Setsuna was fast in her testing. Some of the other students were mesmerized by the finesse of her hands. When she finished she sat her pencil down and looked up only to flinch seeing Shin already headed for the door. She wasted no time taking Yukio her test following Shin out of the cram school.

“Stop right there.” Setsuna called at Shin.

“I was going to introduce myself later.” Shin smiled turning around.

“Your shirt is untucked… your blazer cuffs are undone… and your collar is popped… you… are… in violation… of the dress code!” Setsuna roared swinging her case at him, but to her shock he stopped her with a single hand.

“I expected more.” Shin stated making her angrier.

“So you aren’t all looks…” Setsuna scoffed flipping the latches to the case.

“You’re gonna start a fight with me? I think our dads might be mixed up if that’s the case.” Shin chuckled.

The greatsword Setsuna pulled from the case had a jet black leather wrap on the handle, a pure silver guard with ceremonial engraving and a matching pommel, and a large pearly white blade with a black cross engraved on both sides.

“That sword… it’s not recorded in the annals of history… just like mine. This sword is called Flame Eater… what’s yours called?” Shin spoke grabbing the hilt of his sword.

“Silver Heart, a sword meant to channel demonic or spiritual energy from the wielder to enhance its edge and durability.” Setsuna told him.

In the air watching with binoculars was Mephisto. A sinister grin was plastered on his face as he sipped a crimson wine. 

“I wonder how this will turn out… will the victor be the authoritarian Setsuna… or the new kid Shinku…” Mephisto chuckled.


	2. The Okumura Cousins

**Summary for the Chapter:**

> Shinku and Setsuna battle, but it ends suddenly.

Setsuna charged Shin and he drew his katana swinging three times at sonic speed knocking her back before sheathing his blade again. She was completely confused as to why he had sheathed his weapon instead of keeping it drawn. Shin looked ready to suddenly draw again as well wearing a focused expression. Was he toying with her or was that really his sword style?

“Draw your sword and keep it out.” Setsuna growled.

“Nah. It’s more fun to see how you’ll work around an obscure sword style. It took me five years to hone it to this level.” Shin smiled.

“Cocky bastard…” Setsuna scoffed.

“Cocky? I just want to see the skill gap between us.” Shin chuckled.

“The skill gap? Oh I’ll show you the skill gap!” Setsuna roared as blue flames erupted from her sword as a demon tail and demon wings sprouted from her uniform.

“So your flames are blue…” Shin smiled.

Setsuna charged unleashing blasts of blue flame with each swing. She was faster and stronger too. Shin drew his blade to stop a swing he couldn’t dodge stopping her cold showing the blade of Flame Eater seemed to be made from black onyx when he wasn’t swinging faster than could be seen. Setsuna roundhouse kicked him and continued her rampage on him only for him to unleash a powerful lash of crimson flames that sent her flying to a tree. The flames that didn’t hit her were then sucked into Flame Eater’s blade turning it red for a few seconds.

“Crap… used my flames by accident…” Shin grimaced.

“You pack some punch, but that won’t be enough to win.” Setsuna scoffed dusting herself off.

She charged again using even more flames with her sword. In a few short minutes she’d already set a ton of trees ablaze trying to hit him. Shin grew more concerned as more trees lit up. All of a sudden a girl student with long red hair exited from the cram school door as flames headed that way. The sight paired with the scream made Shin’s eyes turn demonic as Yukio came sprinting.

“Moron, wandering onto a battlefield…” Setsuna scoffed.

“Setsuna… you’re exactly the kind of half-demon that I’m sick of people thinking represents us!” Shin roared as the flame of his tail flared to match his emotions.

Black horns grew from Shin’s head that immediately lit with flaring crimson flames startling Setsuna. He was far stronger now knocking her around with single swings. His swordsmanship was easily on par with her mother’s despite his furious state. Flames were erupting from his body that Flame Eater was eating at rapid pace turning the entire blade red emitting sparks and smoke each time it met Setsuna’s blade.

“What is this…? My flames can’t be beaten… can they…?” Setsuna thought in a panic.

To her shock the Flame Eater cut through her blade and made a long slash wound on her body that was cauterized instantaneously by the heat. Setsuna fell to her knees shaking as Shin swung his blade in the air drawing Setsuna’s flames to it in order to put out the fires. Yukio opened a door to the medical wing of True Cross and hurried both the student and Setsuna through. Mephisto soon arrived to visit Yukio, who had Shin sitting by him.

“To think, this happened over something as simple as a dress code violation. I hope this makes her realize her achilles heel.” Mephisto sighed sipping some tea.

“I knew Setsuna was being too strict… but starting a fight with demonic powers over it?” Yukio questioned staring at his sleeping daughter.

“I ordinarily wouldn’t tell anyone, but I let them fight.” Mephisto admitted to him.

“Why?!” Yukio asked in shock.

“Someone needed to teach Setsuna a lesson. You may be her father but with your position as a teacher you wouldn’t be able to lay a finger on her. That was when your nephew came along. He was a fellow student and more than a match for her. Laid back and friendly, I knew sooner or later they would clash. Still, they lasted longer than I expected. I bet the day he came to the academy they’d fight.” Mephisto explained to him.

“Sir, what’s the condition of the girl she burned?” Shin asked standing up.

“Well, they were demonic flames, so understandably she received a very nasty temptaint because of it. We can treat the infection but I’m afraid she’ll have permanent scarring and burn deformation. Depending on how things go, Setsuna may be ordered to appear before the Vatican to stand trial for her carelessness.” Mephisto answered.

“Depending on what things?” Yukio asked nervously.

“Mainly if her victim wants to press charges. In the old days that’d be more than enough to get her executed, but things are different since Rin’s visits to the Vatican. Half-demons aren’t treated quite as rough now, but it’s still very stacked in regards to the odds.” Mephisto explained to him.

“Would there even be a trial if we know she’s guilty?” Yukio asked.

“Where’d Shin go?” Mephisto asked making Yukio look where an outline of him is flashing.

Across the medical wing Shin had gone to see the wounded student, who was resting after receiving treatment. The left half of her face was hidden under bandages along with most of her torso. Shin sat down by her remaining silent. A male exorcist with messy blonde hair smoking a cigarette entered shortly after using the ashtray to put it out.

“So the authoritarian burned her, eh? Well I guess this solves one of her issues…” the exorcist sighed.

“Issues?” Shin asked.

“This girl is ‘behind’ shall we say? She was too afraid to receive her temptaint on the day the rest got theirs, so she’s had to sit out a lot even though she knows the stuff. Okumura’s tried to convince her numerous times, but every time she’s wimped out. In a way I guess it was bound to happen eventually.” the exorcist answered.

“Would she press charges on Setsuna?” Shin asked.

“Luka wouldn’t do that. She understands that it was an accident, plus it got her off the fence she was sitting on.” the exorcist assured him.

“How do you know?” Shin asked curiously.

“I was able to ask her a few questions before her meds kicked in. She’ll need glasses once she recovers due to damage suffered to her left eye from the flames though.” the exorcist answered.

“I hope she doesn’t hate half-demons after this…” Shin grimaced.

“I doubt it. She’s the daughter of an exorcist who understands that not all demons are evil after all. She’s a bit nervous around new people, but once she gets used to you she can stand her ground like anyone else at the academy.” the exorcist assured him.

“By chance are you her father?” Shin asked him.

“Me? Nah, but I am close with her old man. He said to look after her while he tracks down her mother.” the exorcist smiled in response.

“Did she leave or something?” Shin asked and the exorcist put a hand on his head.

“Sorry. Her old man told me specifically not to tell anyone who doesn’t need to know… including her.” the exorcist smiled before leaving the room.

The following day it became common knowledge that Shin and Setsuna were related. It quickly became the source of many rumors, especially since Setsuna’s injury became known as well. On the sixth day since the fight…

“You’re Shinku Okumura?!” an angry girl asked with a mob behind her.

“Yeah. Can I help you?” Shin asked with a mouth full of sandwich.

“You dare to put even a scratch on Lady Setsuna’s body?! That injury is going to leave a scar! You think you can do that and not receive recompense for your actions?! We are the Beauty Preservation Club, and we will not abide such savagery!” the girl roared as the mob roared with her.

“Time to go…” Shin nervously chuckled before taking off full speed.

The mob chased him all over campus. His stamina astounded some of the track kids who saw the spectacle. The final bell rung when at last the mob was too worn out to continue giving chase. Shin had only worked up a light sweat which seemed to rub salt in the wound. After a quick return to his dorm to bathe and change clothes, he went to the cram school.

“Shinku, why are you late and not in uniform?” Yukio asked him.

“Had an angry mob chasing me the whole day so I was understandably sweaty. I felt that I should freshen up before coming to class today.” Shin answered.

“Fine. Have someone let you copy their notes from the first part of the lecture.” Yukio instructed.

The next few days had the mob chasing Shin continuously. They just didn’t seem to give up. He was going through clothes much faster because of them too and kept showing up late for cram school. On the day Setsuna was discharged from the hospital wing she waited at the door to the cram school for the usual end of the chase...

“Open the door open the door!” Shin cried as he ran toward her.

“No. This must be dealt with.” Setsuna spoke walking toward him and the mob letting him go right past her.

“What do you mean?” Shin asked skidding to a stop.

“BY THE AUTHORITY OF THE STUDENT COUNCIL I ORDER YOU TO STOP!!!” Setsuna roared making the mob skid to a halt.

“Lady Setsuna…” the head of the mob gasped.

“Look at you all, armed to the teeth all because I was wounded. You act like I’m some big shot, forming a mob all to attack one person… you’re no better than Yakuza acting this way! A scar is a scar and it will never leave my body, a reminder of my own foolishness! I despise this cousin of mine… but what I did was careless! I allowed myself to become so absorbed in fighting him that I neglected to take caution once a noncombatant unwittingly entered the battlefield!” Setsuna lectured them.

“He ruined your perfect body…” the head of the mob whimpered.

“Your pettiness is an eyesore. I hereby disband the Beauty Preservation Club under the pretenses of violating the Bully Act and Lawful Society Act of the academy!” Setsuna roared making the mob disperse crying.

“You saved my bacon…” Shin sighed.

“Don’t get me wrong. I will pay you back for this scar, but I am going to personally deliver the blow. No other will be allowed to do it and I’ll be sure that no one will be in range of the battle.” Setsuna scoffed as she opened the door to the cram school.

“Well, as long as no one else gets hurt…” Shin sighed entering after her.


End file.
